HPLC vs Mass Spec: How Peptide Purity Is Tested
Two tests do most of the work on a peptide Certificate of Analysis: HPLC and mass spectrometry. They answer different questions, and a serious COA uses both. Here is what each proves. (Research-use context only.)
HPLC: how pure is it?
High-performance liquid chromatography separates the components of a sample as they pass through a column, producing a chromatogram of peaks. The target peptide is the main peak, and its area relative to the rest gives the purity percentage. HPLC answers “how much of this is the peptide, and how much is impurity?”
Mass spectrometry: is it the right molecule?
Mass spectrometry measures molecular weight. By comparing the observed mass to the theoretical mass of the intended sequence, it confirms identity — that the material is the peptide on the label. HPLC can tell you a sample is 99% one thing; only mass spec tells you that one thing is the correct molecule.
Why you want both
Purity without identity is meaningless, and identity without purity is incomplete. A COA reporting HPLC purity and mass-spec identity — ideally from an independent lab — is the standard worth holding suppliers to. See the full COA guide →
This combined standard is how every batch in the Life Link Research catalog is tested, and it is the same characterization the FDA’s reviewers emphasized in the 2026 peptide review.
Research use only. Peptides and related materials referenced are intended for in-vitro laboratory research only — not for human or veterinary use, diagnosis, treatment, or consumption. This guide is general educational information, not medical or purchasing advice.
